body, 
div,
section,
ul,
li,
p,
main,
nav,
header,
footer,
a,
span,
b {
    box-sizing: border-box;
    padding: 0;
    margin: 0;
}
#root,
.app-inner {
    height: 100%;
}
.clearfix:after {
    content: '';
    display: block;
    clear: both;
}